Table 1. Three structures of MMP-1 (PDB: 966C), MMP-3 (PDB: 1G4K) and MMP-9 (PDB: 2OW0) as targets for anti-aging drug discovery

Protein	PDB id	Resolution	Structure type	Selected chain for docking	Co-crystallized ligand	Reference
MMP-1	966C	1.9 Å	Monomer A	Monomer A	N-hydroxy-2-[4-(4-phenoxy-benzenesulfonyl)-tetrahydro-pyran-4-yl]-acetamide	[11]
MMP-3	1G4K	2.0 Å	Trimer A, B, C	Chain B	5-methyl-5-(4-phenoxy-phenyl)-pyrimidine-2,4,6-trione	[12]
MMP-9	2OW0	2,.0 Å	Dimer A, B	Chain A	N-[(4’-iodobiphenyl-4-yl)sulfonyl]-d-tryptophan	[13]